Method for producing a branch pipe

Abstract

The invention relates to a method for producing a branch pipe. In order for the dependable production of a branch pipe with virtually any desired design of the branch to be made possible in a simple way it is proposed that an elongate, straight main curvature and at least two lateral curvatures, respectively branching off from a longitudinal side of the main curvature, lying opposite each other with respect to the central longitudinal axis of the main curvature extending in the material of the blank and having a mirror-symmetrically arranged base line are formed from a blank by deep-drawing. After the forming operations, the blank is trimmed in such a way that a vessel-like shell part, which is open in the longitudinal direction, is formed from the main curvature, and half-sleeves, which adjoin the shell part, lie in the same plane as the shell part and are open in the direction of their extent, are formed from the lateral curvatures, and that sheet metal strips serving as joining flanges extend along the outside of the lateral edges of the shell part and the half-sleeves. Subsequently, the shell part is bent about a spatial axis parallel to the central longitudinal axis until the joining flanges corresponding to one another on both sides of the shell part lie against one another, and, after that, the joining flanges are connected to one another.

1 - 3 . (canceled)  
   
   
       4 . A method for producing a branch pipe adapted to be located in the exhaust line of a motor vehicle, comprising: 
 forming an elongate, straight main curvature and at least two lateral curvatures, branching off from the longitudinal sides of the main curvature, lying opposite each other with respect to the central longitudinal axis of the main curvature extending in the material of a blank, and having a mirror-symmetrically arranged base line, from a blank by deep drawing,    trimming the blank in such a way that a vessel-like shell part, which is open in the longitudinal direction, is formed from the main curvature, half-sleeves, which adjoin the shell part, lie in the same plane as the shell part and are open in the direction of their extent, are formed from the lateral curvatures, and sheet metal strips serving as joining flanges extend along the outside of the lateral edges of the shell part and the half-sleeves,    subsequently bending the shell part about a spatial axis parallel to the central longitudinal axis until the joining flanges corresponding to one another on both sides of the shell part lie against one another, and    connecting the joining flanges to one another by clinch-joining.    
   
   
       5 . The method as claimed in  claim 4 , wherein an end of the sheet metal strip running along the half-sleeve is drawn back with respect to an edge of the opening of the half-sleeve.  
   
   
       6 . A branch pipe produced by the method of  claim 4 .  
   
   
       7 . A branch pipe provided by the method of  claim 5.